Conventional toothbrushes typically are arranged to mechanically scrub the surfaces of the teeth to remove dental plaque. A variety of bristle materials, bristle dimensions and bristle geometry have been used to facilitate the cleaning process and are disclosed in many patents. Typically, the bristle design results in a sweeping motion of the bristles over the face of the teeth. Alternatively, arrangements such as shown in U.S. Pat. No. 7,520,016 separately drive regions or portions of the bristle set along different axes simultaneously in attempt to achieve a more efficient or more effective cleaning.
Relative to the toothbrush appliance itself, the natural resonant frequency of the various components of a power toothbrush are typically avoided when the drive frequency for the appliance is selected, due to either detrimental or unpredictable effects on device performance and longevity. Undesirable effects include excessive noise, unpleasant user experience and inadequate cleaning. Early failure of the appliance may be caused by excessive vibration of the drive train. The resonant frequency of the handle is the most significant component frequency, although the resonant frequency of the brushhead is usually considered as well. It is typically best practice to avoid matching the resonant frequencies of these two major components.
The effect of the resonant frequency on motion of the bristles has not been heretofore thoroughly investigated relative to cleaning efficiency and/or effectiveness, since the motion has heretofore been primarily determined by the structure of the brushhead itself. A thorough investigation of various aspects of the bristles themselves may, however, result in more effective cleaning while avoiding the performance disadvantages mentioned above. Hence, it would be desirable to improve appliance performance by determining various advantageous structural aspects and arrangements of bristles construction and attachment.